[HINT] TWinControl.CreateWnd creating Handle during loading PGC_H:TTabControl csDesigning=False
QCoreApplication::postEvent: Unexpected null receiver ...
reopen form I get this error
[HINT] TWinControl.CreateWnd creating Handle during loading PGC_H:TTabControl csDesigning=False
TApplication.HandleException Access violation
Stack trace:
$00007F67CF31211D
...

After form destroy I get this errors. Form is not autocreate, when I
need then create and onformclose use cafree, ondestroy event myform := nil;

[HINT] TWinControl.CreateWnd creating Handle during loading

It means your control is already doing things, while some properties don't have their value yet.

Mattias